Electronic device with dual clutch barrel cavity antennas

ABSTRACT

An electronic device has antennas formed from cavity antenna structures. The electronic device may have a metal housing. The metal housing may have an upper housing in which a component such as a display is mounted and a lower housing in which a component such as a keyboard is mounted. Hinges may be used to mount the upper housing to the lower housing for rotation about a rotational axis. Cavity antennas may be formed in a clutch barrel region located between the hinges and running along the rotational axis. A flexible printed circuit may be formed between the cavity antennas. Each cavity antenna may have a first end that is adjacent to one of the hinges and a second end that is adjacent to the flexible printed circuit. Cavity walls for the cavity antennas may be formed from metal housing structures such as metal portions of the lower housing.

This application is a continuation of patent application Ser. No.14/202,860, filed Mar. 10, 2014, which is hereby incorporated byreference herein in its entirety.

BACKGROUND

This relates generally to electronic devices and, more particularly, toelectronic devices with antennas.

Electronic devices often include antennas. For example, cellulartelephones, computers, and other devices often contain antennas forsupporting wireless communications.

It can be challenging to form electronic device antenna structures withdesired attributes. In some wireless devices, the presence of conductivehousing structures can influence antenna performance. Antennaperformance may not be satisfactory if the housing structures are notconfigured properly and interfere with antenna operation. Device sizecan also affect performance. It can be difficult to achieve desiredperformance levels in a compact device, particularly when the compactdevice has conductive housing structures.

It would therefore be desirable to be able to provide improved wirelesscircuitry for electronic devices such as electronic devices that includeconductive housing structures.

SUMMARY

An electronic device such as a portable computer may be provided withantennas. The antennas may be cavity antennas. Each cavity antenna mayhave a metal cavity structure that defines an antenna cavity and mayhave an antenna resonating element that is mounted within the cavity.

The electronic device may have a metal housing. The metal housing mayhave an upper housing in which a component such as a display is mountedand a lower housing in which a component such as a keyboard is mounted.Hinges may be used to mount the upper housing to the lower housing.Cavity antennas may be formed in a clutch barrel region located betweenthe hinges. Cavity structures may be formed from metal portions of thehousing such as portions of the lower housing.

A flexible printed circuit may be formed between first and second cavityantennas. Each cavity antenna may have an outer end that is adjacent toone of the hinges and an inner end that is adjacent to the flexibleprinted circuit.

Components such as speakers may be mounted within antenna cavities. Thespeakers may be isolated from the antennas using inductors.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an illustrative electronic device suchas a laptop computer in accordance with an embodiment.

FIG. 2 is a schematic diagram of an illustrative electronic device withwireless circuitry in accordance with an embodiment.

FIG. 3 is a perspective view of an illustrative hinge of the type thatmay be used in an electronic device with housing portions that rotaterelative to each other in accordance with an embodiment.

FIG. 4 is a perspective view of an illustrative electronic device suchas a portable computer showing how the electronic device may have aclutch barrel region in which antennas can be formed in accordance withan embodiment.

FIG. 5 is a diagram of an illustrative inverted-F antenna in accordancewith an embodiment.

FIG. 6 is a perspective view of an illustrative cavity antenna inaccordance with an embodiment.

FIG. 7 is a cross-sectional side view of an illustrative cavity antennasuch as the cavity antenna of FIG. 6 in accordance with an embodiment.

FIG. 8 is a cross-sectional side view of an illustrative electronicdevice such as a portable computer having a lid in a closed position andhaving antenna structures in accordance with an embodiment.

FIG. 9 is a cross-sectional side view of an illustrative electronicdevice such as a portable computer having a lid in an open position andhaving antenna structures in accordance with an embodiment.

FIG. 10 is a top view of an illustrative electronic device such as aportable computer with its lid in an open position showing how a clutchbarrel portion of the electronic device can be divided into two antennacavities by a flexible printed circuit between the antenna cavities inaccordance with an embodiment.

FIG. 11 is a cross-sectional side view of an illustrative electronicdevice such as a portable computer showing how components such aselectrically isolated speakers may float within an antenna cavity inaccordance with an embodiment.

DETAILED DESCRIPTION

An electronic device such as electronic device 10 of FIG. 1 may containwireless circuitry. For example, electronic device 10 may containwireless communications circuitry that operates in long-rangecommunications bands such as cellular telephone bands and wirelesscircuitry that operates in short-range communications bands such as the2.4 GHz Bluetooth® band and the 2.4 GHz and 5 GHz WiFi® wireless localarea network bands (sometimes referred to as IEEE 802.11 bands orwireless local area network communications bands). Device 10 may alsocontain wireless communications circuitry for implementing near-fieldcommunications, communications at 60 GHz, light-based wirelesscommunications, satellite navigation system communications, or otherwireless communications.

Device 10 may be a handheld electronic device such as a cellulartelephone, media player, gaming device, or other device, may be a laptopcomputer, tablet computer, or other portable computer, may be a desktopcomputer, may be a computer display, may be a display containing anembedded computer, may be a television or set top box, or may be otherelectronic equipment. Configurations in which device 10 has a rotatablelid as in a portable computer are sometimes described herein as anexample. This is, however, merely illustrative. Device 10 may be anysuitable electronic equipment.

As shown in the example of FIG. 1, device 10 may have a housing such ashousing 12. Housing 12 may be formed from plastic, metal (e.g.,aluminum), fiber composites such as carbon fiber, glass, ceramic, othermaterials, and combinations of these materials. Housing 12 or parts ofhousing 12 may be formed using a unibody construction in which housingstructures are formed from an integrated piece of material. Multiparthousing constructions may also be used in which housing 12 or parts ofhousing 12 are formed from frame structures, housing walls, and othercomponents that are attached to each other using fasteners, adhesive,and other attachment mechanisms.

Some of the structures in housing 12 may be conductive. For example,metal parts of housing 12 such as metal housing walls may be conductive.Other parts of housing 12 may be formed from dielectric material such asplastic, glass, ceramic, non-conducting composites, etc. To ensure thatantenna structures in device 10 function properly, care should be takenwhen placing the antenna structures relative to the conductive portionsof housing 12. If desired, portions of housing 12 may form part of theantenna structures for device 10. For example, conductive housingsidewalls may form an antenna ground element. The antenna ground elementmay be configured to form one or more cavities for cavity-backedantennas. The cavities in the cavity-backed antennas may be formed fromportions of housing 12 located between hinges in a portable computerand/or other conductive electronic device structures.

As shown in FIG. 1, device 10 may have input-output devices such astrack pad 18 and keyboard 16. Camera 26 may be used to gather imagedata. Device 10 may also have components such as microphones, speakers,buttons, removable storage drives, status indicator lights, buzzers,sensors, and other input-output devices. These devices may be used togather input for device 10 and may be used to supply a user of device 10with output. Ports in device 10 such as ports 28 may receive matingconnectors (e.g., an audio plug, a connector associated with a datacable such as a Universal Serial Bus cable, a data cable that handlesvideo and audio data such as a cable that connects device 10 to acomputer display, television, or other monitor, etc.).

Device 10 may include a display such a display 14. Display 14 may be aliquid crystal display (LCD), a plasma display, an organiclight-emitting diode (OLED) display, an electronic ink display, or adisplay implemented using other display technologies. A touch sensor maybe incorporated into display 14 (i.e., display 14 may be a touch screendisplay). Touch sensors for display 14 may be resistive touch sensors,capacitive touch sensors, acoustic touch sensors, light-based touchsensors, force sensors, or touch sensors implemented using other touchtechnologies.

Device 10 may have a one-piece housing or a multi-piece housing. Asshown in FIG. 1, for example, electronic device 10 may be a device suchas a portable computer or other device that has a two-part housingformed from upper housing 12A and lower housing 12B. Upper housing 12Amay include display 14 and may sometimes be referred to as a displayhousing or lid. Lower housing 12B may sometimes be referred to as a baseor main housing. Housings 12A and 12B may be connected to each otherusing a hinge (e.g., a hinge located in region 20 along the upper edgeof lower housing 12B and the lower edge of upper housing 12A). The hingemay allow upper housing 12A to rotate about axis 22 in directions 24relative to lower housing 12B. The plane of lid (upper housing) 12A andthe plane of lower housing 12B may be separated by an angle that variesbetween 0° when the lid is closed to 90°, 140°, or more when the lid isfully opened.

A schematic diagram showing illustrative components that may be used indevice 10 is shown in FIG. 2. As shown in FIG. 2, device 10 may includecontrol circuitry such as storage and processing circuitry 30. Storageand processing circuitry 30 may include storage such as hard disk drivestorage, nonvolatile memory (e.g., flash memory or otherelectrically-programmable-read-only memory configured to form a solidstate drive), volatile memory (e.g., static or dynamicrandom-access-memory), etc. Processing circuitry in storage andprocessing circuitry 30 may be used to control the operation of device10. This processing circuitry may be based on one or moremicroprocessors, microcontrollers, digital signal processors,application specific integrated circuits, etc.

Storage and processing circuitry 30 may be used to run software ondevice 10, such as internet browsing applications,voice-over-internet-protocol (VOIP) telephone call applications, emailapplications, media playback applications, operating system functions,etc. To support interactions with external equipment, storage andprocessing circuitry 30 may be used in implementing communicationsprotocols. Communications protocols that may be implemented usingstorage and processing circuitry 30 include internet protocols, wirelesslocal area network protocols (e.g., IEEE 802.11 protocols—sometimesreferred to as WiFi®), protocols for other short-range wirelesscommunications links such as the Bluetooth® protocol, cellular telephoneprotocols, MIMO protocols, antenna diversity protocols, etc.

Input-output circuitry 44 may include input-output devices 32.Input-output devices 32 may be used to allow data to be supplied todevice 10 and to allow data to be provided from device 10 to externaldevices. Input-output devices 32 may include user interface devices,data port devices, and other input-output components. For example,input-output devices may include touch screens, displays without touchsensor capabilities, buttons, joysticks, click wheels, scrolling wheels,touch pads, key pads, keyboards, microphones, cameras, buttons,speakers, status indicators, light sources, audio jacks and other audioport components, digital data port devices, light sensors, motionsensors (accelerometers), capacitance sensors, proximity sensors, etc.

Input-output circuitry 44 may include wireless communications circuitry34 for communicating wirelessly with external equipment. Wirelesscommunications circuitry 34 may include radio-frequency (RF) transceivercircuitry formed from one or more integrated circuits, power amplifiercircuitry, low-noise input amplifiers, passive RF components, one ormore antennas, transmission lines, and other circuitry for handling RFwireless signals. Wireless signals can also be sent using light (e.g.,using infrared communications).

Wireless communications circuitry 34 may include radio-frequencytransceiver circuitry 90 for handling various radio-frequencycommunications bands. For example, circuitry 34 may include transceivercircuitry 36, 38, and 42. Transceiver circuitry 36 may be wireless localarea network transceiver circuitry that may handle 2.4 GHz and 5 GHzbands for WiFi® (IEEE 802.11) communications and that may handle the 2.4GHz Bluetooth® communications band. Circuitry 34 may use cellulartelephone transceiver circuitry 38 for handling wireless communicationsin frequency ranges such as a low communications band from 700 to 960MHz, a midband from 1710 to 2170 MHz, and a high band from 2300 to 2700MHz or other communications bands between 700 MHz and 2700 MHz or othersuitable frequencies (as examples). Circuitry 38 may handle voice dataand non-voice data. Wireless communications circuitry 34 can includecircuitry for other short-range and long-range wireless links ifdesired. For example, wireless communications circuitry 34 may include60 GHz transceiver circuitry, circuitry for receiving television andradio signals, paging system transceivers, near field communications(NFC) circuitry, etc. Wireless communications circuitry 34 may includesatellite navigation system circuitry such as global positioning system(GPS) receiver circuitry 42 for receiving GPS signals at 1575 MHz or forhandling other satellite positioning data. In WiFi® and Bluetooth® linksand other short-range wireless links, wireless signals are typicallyused to convey data over tens or hundreds of feet. In cellular telephonelinks and other long-range links, wireless signals are typically used toconvey data over thousands of feet or miles.

Wireless communications circuitry 34 may include antennas 40. Antennas40 may be formed using any suitable antenna types. For example, antennas40 may include antennas with resonating elements that are formed fromloop antenna structures, patch antenna structures, inverted-F antennastructures, slot antenna structures, planar inverted-F antennastructures, helical antenna structures, hybrids of these designs, etc.If desired, one or more of antennas 40 may be cavity-backed antennas.Different types of antennas may be used for different bands andcombinations of bands. For example, one type of antenna may be used informing a local wireless link antenna and another type of antenna may beused in forming a remote wireless link antenna.

Transmission line paths may be used to couple antenna structures 40 totransceiver circuitry 90. Transmission lines in device 10 may includecoaxial cable paths, microstrip transmission lines, striplinetransmission lines, edge-coupled microstrip transmission lines,edge-coupled stripline transmission lines, transmission lines formedfrom combinations of transmission lines of these types, etc. Filtercircuitry, switching circuitry, impedance matching circuitry, and othercircuitry may be interposed within the transmission lines, if desired.

Hinges may be used to allow portions of an electronic device to rotaterelative to each other. Hinges may, for example, be used to allow upperhousing 12A of FIG. 1 to rotate relative to lower housing 12B aboutrotational axis 22. The hinge structures that are used to attachhousings 12A and 12B together are sometimes referred to as clutchstructures or clutches. An illustrative clutch (hinge) is shown in FIG.3. As shown in FIG. 3, clutch (hinge) 56 may have a structure such asstructure 54 and a structure such as structure 46 that rotate relativeto each other about axis 22. Structure 54 may have holes such as holes58 that receive screws. The screws may be used to attach structure 54 toframe structure 12A-1 or other structures in upper housing 12A.Structure 46 may be attached to housing 12B using screws that passthrough holes 48. If desired, other attachment techniques may be used tomount structure 54 to housing 12A and to mount structure 46 to housing12B. The use of screws is merely illustrative.

Structure 54, which may sometimes referred to as a clutch pillar, mayinclude shaft 50. Structure 46, which may sometimes be referred to as aclutch band, may have portions 52 that grip shaft 50 with apredetermined amount of friction. During operation, the clutch bandholds the clutch pillar with an amount of force that allows upperhousing 12A to rotate relative to lower housing 12B. Sufficient frictionis present to allow a user to place upper housing 12A at a desired anglerelative to lower housing 12B without slipping. Structure 12A-1 may beattached to other structures in housing 12A such as display 14, housingwall structures (e.g., metal housing structures), etc. The portions ofhousing 12B that are attached to structure 46 may include housingstructures such as a metal frame, metal sidewalls, and other housingstructures.

A pair of hinge structures such as hinge 56 of FIG. 3 may be mountedwithin portions of housing 12 to form a hinge for device 10. As shown inFIG. 4, for example, hinge structures 56 may be mounted at either end ofa region in housing 12 such as clutch barrel region 60 (i.e., a hingefor device 10 may be formed by placing a structure such as hinge 56 ofFIG. 3 at each of the two opposing ends of clutch barrel 60). Clutchbarrel 60 may have a cylindrical shape as shown in FIG. 4 or may haveother shapes. Clutch barrel 60 may have a dielectric cover portionand/or may be formed form metal. For example, in configurations in whichhousing 12 is formed from metal, clutch barrel 60 may be part of housing12A, may be part of housing 12B, may contain metal parts that areintegral to both housing 12A and 12B, and/or may be formed from metalstructures that are separate from housing 12A and 12B.

The portions of housing 12 surrounding clutch barrel 60 may beconfigured to form one or more cavities for cavity backed antennas. Forexample, a pair of cavity antennas may be formed in region 60. Thecavities may have elongated shapes that run parallel to axis 22. One ofhinges 56 may be located at the outer end of each cavity antenna. Aconductive structure such as a printed circuit may be located betweenthe cavities in the middle of clutch barrel 60.

Antenna structures may also be mounted at other locations within device10 such as along the upper edge of display 12 (e.g., under the upperbezel of housing 12A), in lower housing 12B, under dielectric windowstructures in housing 12A or housing 12B, behind layers of glass orother dielectrics, or elsewhere in housing 12. An advantage of mountingantenna structures within the clutch barrel is that this location maypermit antenna operation both when lid 12A is open and when lid 12A isclosed.

Antenna structures in clutch barrel 60 may include dielectric materials(e.g., a dielectric carrier such as a plastic carrier for supportingpatterned conductive antenna structures, a plastic cover or a coverformed from other dielectrics, etc.). Air (which is a dielectric) mayalso be present within clutch barrel 60 (e.g., in an antenna cavity).Surrounding portions of device 10 may be substantially conductive. Forexample, structures in upper housing 12A such as frame 12A-1 of FIG. 3,display 14 of FIG. 1, and housing sidewalls for housing 12 in whichdisplay 14 and frame 12A-1 are mounted may all be conductive (e.g.,metal). Likewise, structures in housing 12B such as metal housingsidewalls, metal frame structures, ground planes on printed circuitboards, radio-frequency shielding structures, and other devicecomponents in housing 12B may be conductive.

The metal structures of housing 12 (e.g., the portions of housing 12around clutch barrel 60) may define antenna cavities and/or slot-shapedfeatures that affect antenna performance. For example, a cavity may beformed that affects how efficiently an antenna may operate at variousdifferent wavelengths. To enhance antenna performance, cavities (andassociated gaps or slots through which the antennas may operate) may beconfigured to support antenna resonances at desired frequencies.

Cavity-backed antennas (sometimes referred to as cavity antennas) areformed from antenna resonating elements located within an antenna groundplane having the shape of a cavity (e.g., a cavity formed from metalhousing 12). The antenna resonating element for a cavity antenna may beformed from a patch antenna resonating element, a monopole antennaresonating element, an inverted-F antenna resonating element, a slotantenna resonating element, or other suitable antenna resonating elementstructures. An illustrative inverted-F antenna of the type that may beused to feed a cavity antenna is shown in FIG. 5. Inverted-F antenna 40Fof FIG. 5 or other suitable antenna structures may be used as an antennafeed for a cavity antenna by placing antenna 40F within a metal cavity.

As shown in FIG. 5, inverted-F antenna element 40F has antennaresonating element 106 and antenna ground (ground plane) 104. Groundplane 104 may be formed from metal housing 12 (e.g., portions of housing12 shaped to form an antenna cavity). Antenna resonating element 106 mayhave a main resonating element arm such as arm 108. The length of arm108 may be selected so that antenna element 40F resonates at desiredoperating frequencies. For example, if the length of arm 108 may be aquarter of a wavelength at a desired operating frequency for antennaelement 40F. Antenna element 40F may also exhibit resonances at harmonicfrequencies.

Main resonating element arm 108 may be coupled to ground 104 by returnpath 110. Antenna feed 112 may include positive antenna feed terminal 98and ground antenna feed terminal 100 and may run in parallel to returnpath 110 between arm 108 and ground 104. If desired, inverted-F antennassuch as illustrative antenna 40F of FIG. 5 may have more than oneresonating arm branch (e.g., to create multiple frequency resonances tosupport operations in multiple communications bands) or may have otherantenna structures (e.g., parasitic antenna resonating elements, tunablecomponents to support antenna tuning, etc.). A planar inverted-F antenna(PIFA) may be formed by implementing arm 108 using planar structures(e.g., a planar metal structure such as a metal patch or strip of metalthat extends into the page of FIG. 5).

FIG. 6 is a perspective view of an illustrative cavity antenna of thetype that may be used in clutch barrel 60 of device 10. Cavity antenna40 of FIG. 6 has cavity structures 200. Cavity structures 200 are formedfrom a conductive material such as metal (e.g. portions of metal housing12 in clutch barrel region 60). Cavity structures 200 in the example ofFIG. 6 form an open-front box having rear wall 200-5, upper wall 200-4,lower wall 200-2, right wall 200-1, and left wall 200-2. In device 10,different cavity shapes may be used (e.g., shapes with curved cavitywalls, etc.). Cavity 206 is a recess formed within the interior ofcavity structures 200. Cavity 206 may be characterized by a longerdimension such as length L, a shorter dimension such as height H, and adepth D. The configuration FIG. 6 is merely illustrative.

Antenna feed structure 40F for cavity antenna 40 may be formed withincavity 206. A cross-sectional side view of the structures of FIG. 6taken along line 202 and viewed in direction 204 is shown in FIG. 7. Asshown in FIG. 7, antenna element 40F (e.g., an inverted-F antennaresonating element or other suitable antenna resonating element) may belocated within cavity 206 in the interior of cavity structures 200.Antenna element 40F serves as a feed for cavity antenna 40. Transmissionline 210 may couple antenna element 40F to radio-frequency transceivercircuitry 90.

Cavity structures 200 may be provided with an opening such as opening208. During operation, incoming antenna signals may be received byelement 40F through opening 208 and transmitted antenna signals fromelement 40F may be emitted through opening 208.

A cross-sectional side view of device 10 showing how a cavity antennafor device 10 of FIG. 1 may be implemented in clutch barrel region 60 isshown in FIG. 8. As shown in FIG. 8, cavity antenna 40 may be formed byplacing antenna feed element 40F within cavity 206. The walls of cavity206 may be formed by metal structures in device 10 such as housing 12.For example, portions of lower housing 12B may be used to define metalwalls for cavity 206. Housing portion 220 may form upper wall 200-4 ofFIG. 7, housing portion 216 may form lower wall 200-2 of FIG. 7, andhousing portion 222 may form rear wall 200-5 of cavity structures 200(as an example). Antenna element 40F may be mounted on a plastic carriersuch as carrier 214 or may be mounted on other suitable supportstructures. If desired, antenna element 40F may be mounted in locationssuch as locations 40F′ of FIG. 8.

Opening 208 of cavity 206 may be formed between portion 220 of housing12B and portion 216 of housing 12B. Portions of housing 12A maypartially block opening 208, but antenna signals may pass through one ormore gaps such as slot-shaped opening 212 (i.e., a gap formed betweenportion 216 of housing 12B and opposing housing portion 218 of housing12A that runs along the rear edge of housing 12 parallel to axis 22).

In the configuration of FIG. 8, lid 12A is in its closed position,resting against lower housing 12B. FIG. 9 is a cross-sectional side viewof the structures of FIG. 8 when lid 12A has been placed in its openposition by rotating lid 12A around hinge axis 22.

In the open-lid configuration of FIG. 9, cavity antenna 40 can operatethrough gaps such as upper gap 226 and lower gap 212 (e.g., slot-shapedopenings that run parallel to axis 22 and that are formed from opposingmetal structures such as portion 220 of housing 12B and portion 224 ofhousing 12A for gap 226 and from opposing metal structures such asportion 216 of housing 12B and portion 218 of housing 12A for gap 212).Gaps such as gaps 226 and 212 may have widths of about 1.2-1.5 mm, ofabout 1-3 mm, of less than 4 mm, of more than 2 mm, or other suitablesize. If desired, portions of housing 12A such as portion 228 of FIG. 9may be formed from a dielectric such as plastic to help enhance theeffective width of gap 226 and thereby enhance antenna efficiency.Dielectric portion 228 is adjacent to rotational axis 222 and whenpresent increases the width of gap 226 (i.e., the spacing between theopposing metal portions of housing 12A and housing 12B). When gap 226 isenlarged, the wireless antenna signals being handled by the cavityantennas can pass through gap 226 without being blocked by metal housingstructures.

FIG. 10 shows how two cavities may be formed within clutch barrel 60. Asshown in FIG. 10, flexible printed circuit 230 may run between lowerhousing 12B and upper housing 12A across clutch barrel region 60. Lowerhousing 12B may include control circuitry and other circuitry mounted onone or more printed circuit substrates. This circuitry may be coupled todisplay 14 using signal paths formed from metal traces 232 on flexibleprinted circuit 230. Flexible printed circuit 230 may be formed from aflexible polymer substrate such as a layer of polyimide or a sheet ofother polymer material. Ground connections 234 in the middle of clutchbarrel 60 may be used to short ground traces on flexible printed circuit230 to housing 12A and to housing 12B.

The presence of flexible printed circuit 230 in the middle of clutchbarrel 60 divides clutch barrel 60 into two parts (i.e., the metalcavity structures formed from housing 12 in clutch barrel region 60 areseparated into two cavities by flexible printed circuit 230, which isgrounded to housing 12B by ground connections 234 that are adjacent tothe two cavities). In this way, the presence of flexible printed circuit230 forms cavity 206A and cavity 206B. Cavity 206A has an inner end thatis formed by flexible printed circuit 230 (i.e., flexible printedcircuit 230 forms cavity wall 200-3 of FIG. 6 for cavity 206A). Cavity206A has an opposing outer end (wall 200-1 of cavity structures 200 ofFIG. 6) that is formed by the left-hand hinge 56 of FIG. 10 and adjacentportions of housing 12. Cavity 206B has an inner end that is formed byflexible printed circuit 230 (i.e., flexible printed circuit 230 formscavity wall 200-1 of FIG. 6 for cavity 206B). Cavity 206B has anopposing outer end (wall 200-3 of cavity structures 200 of FIG. 6) thatis formed by the right-hand hinge 56 of FIG. 10 and adjacent portions ofhousing 12. Cavities 206A and 206B are located between respective hinges56 and are separated by flexible printed circuit 230.

Cavity 206A is used in forming first cavity antenna 40A and cavity 206Bis used in forming second cavity antenna 40B. Antennas 40A and 40B maybe cavity antennas such as illustrative cavity antenna 40 of FIGS. 8 and9 (as an example). To enhance antenna efficiency, it may be desirable toconfigure the size of cavities 206A and 206B to allow antennas 40A and40B to operate at desired communications frequencies. As an example, itmay be desirable for length L (i.e., the length of each cavity and thelength of associated slots such as slots 226 and 212, which iseffectively half of the perimeter of the cavities and slots inconfigurations in which the cavities are elongated) to be equal to onewavelength at a communications band frequency of interest. Other cavityshapes may be used if desired. With one suitable arrangement, antennas40A and 40B may be dual band wireless local area network antennas (e.g.,WiFi® antennas) operating at frequencies such as 2.4 GHz and 5 GHz.

As shown in the example of FIG. 11, an audio component such as speaker240 may be mounted within cavity 206 of cavity antenna 40. Inductors 242may be interposed in the pair of signal paths coupling speaker 240 toaudio circuitry 242. At frequencies associated with the antenna signalshandled by antenna 40, inductors 242 will exhibit high impedances. Theconfiguration of FIG. 11 therefore allows speaker 240 to electricallyfloat within cavity 206 and prevents speaker 240 from interfering withthe operation of antenna 40. The arrangement for FIG. 11 may be used forantenna 40A and for antenna 40B of FIG. 10 (i.e., one or more speakers240 may be mounted in each antenna cavity).

The foregoing is merely illustrative and various modifications can bemade by those skilled in the art without departing from the scope andspirit of the described embodiments. The foregoing embodiments may beimplemented individually or in any combination.

What is claimed is:
 1. A portable computer, comprising: a metal housing having an upper metal housing portion that contains a display and having a lower metal housing portion that contains a keyboard; hinges that connect the upper metal housing portion to the lower metal housing portion, wherein the upper metal housing portion rotates relative to the lower metal housing portion about a rotational axis between a closed position and an open position, and there is a gap between opposing metal portions of the upper and lower metal housing portions when the upper metal housing portion is in the closed position through which antenna signals pass; first and second antennas in the lower housing portion between the hinges that transmit and receive the antenna signals; control circuitry in the lower housing portion; and a flexible printed circuit that is coupled between the control circuitry and the display and that runs across the gap between the first and second antennas, wherein the flexible printed circuit includes metal traces that are shorted to the upper metal housing portion and the lower metal housing portion, the metal traces are interposed between the first and second antennas, the metal traces divide the gap into a first portion and a second portion, the first antenna transmits and receives the antenna signals through the first portion of the gap, and the second antenna transmits and receives the antenna signals through the second portion of the gap.
 2. The portable computer defined in claim 1 wherein the gap has a slot shape that runs parallel to the rotational axis.
 3. The portable computer defined in claim 2 wherein the first and second antennas comprise dual band antennas.
 4. The portable computer defined in claim 3 wherein the first and second antennas transmit and receive the antenna signals in communications bands at 2.4 GHz and 5 GHz.
 5. The portable computer defined in claim 4 wherein the first and second antennas comprise cavity antennas.
 6. A portable computer, comprising: a display; an upper metal housing in which the display is mounted; a keyboard; a lower metal housing in which the keyboard is mounted; hinges that connect the upper metal housing to the lower metal housing, wherein the upper metal housing rotates relative to the lower metal housing about a rotational axis between a closed position and an open position, and there is a slot between opposing metal portions of the upper and lower metal housing portions that runs parallel to the rotational axis; first and second cavity antennas in the lower metal housing between the hinges that transmit and receive antenna signals through the slot; and control circuitry in the lower housing portion; and a flexible printed circuit that is coupled between the control circuitry and the display and that runs across the slot between the first and second cavity antennas, wherein the flexible printed circuit includes ground traces that are shorted to the upper metal housing and to the lower metal housing, and the flexible printed circuit forms at least part of an end of the first and second cavity antennas.
 7. The portable computer defined in claim 6 wherein the flexible printed circuit includes metal traces that are shorted to the upper metal housing and the lower metal housing.
 8. The portable computer defined in claim 7 wherein the first and second antennas transmit and receive the antenna signals in communications bands at 2.4 GHz and 5 GHz.
 9. A portable computer, comprising: a metal housing having an upper metal housing portion that contains a display and having a lower metal housing portion that contains a keyboard; hinges that connect the upper metal housing portion to the lower metal housing portion, wherein the upper metal housing portion rotates relative to the lower metal housing portion about a rotational axis between a closed position and an open position, and there is a gap between opposing metal portions of the upper and lower metal housing portions when the upper metal housing portion is in the closed position through which antenna signals pass; first and second antennas in the lower housing portion between the hinges that transmit and receive the antenna signals; control circuitry in the lower housing portion; and a flexible printed circuit that is coupled between the control circuitry and the display and that runs across the gap between the first and second antennas, wherein the flexible printed circuit includes metal traces that are shorted to the upper metal housing portion and the lower metal housing portion, the metal traces are interposed between the first and second antennas, the metal traces are shorted to the lower metal housing portion at first and second grounding locations, the first grounding location is interposed between the second grounding location and the first antenna, and the second grounding location is interposed between the first grounding location and the second antenna.
 10. A portable computer, comprising: a metal housing having an upper metal housing portion that contains a display and having a lower metal housing portion that contains a keyboard; hinges that connect the upper metal housing portion to the lower metal housing portion, wherein the upper metal housing portion rotates relative to the lower metal housing portion about a rotational axis between a closed position and an open position, and there is a gap between opposing metal portions of the upper and lower metal housing portions when the upper metal housing portion is in the closed position through which antenna signals pass; first and second antennas in the lower housing portion between the hinges that transmit and receive the antenna signals; control circuitry in the lower housing portion; and a flexible printed circuit that is coupled between the control circuitry and the display and that runs across the gap between the first and second antennas, wherein the flexible printed circuit includes metal traces that are shorted to the upper metal housing portion and the lower metal housing portion, the metal traces are interposed between the first and second antennas, the lower metal housing portion has opposing first and second conductive surfaces, the first antenna comprises a first antenna resonating element, the second antenna comprises a second antenna resonating element, an entirety of the first antenna resonating element is interposed between the first and second conductive surfaces of the lower metal housing portion, and an entirety of the second antenna resonating element is interposed between the first and second conductive surfaces of the lower metal housing portion. 